Chair control



Feb. 11, 1964 R. H. SAVAGE 3,

CHAIR CONTROL Filed May 23, 1961 2 Sheets-Sheet 1 lilllbllHIf llllINVENTOR. Pas/5K7 /7. 541 465 R. H. SAVAGE CHAIR CONTROL Feb. 11, 1964 2Sheets-Sheet 2 Filed May 23, 1961 INVENTOR. 05527 541/465 BY UnitedStates Patent Ofiice 3,129,942 Patented Feb. 11, 1964 3,120,942 CHCONTROL Robert H. Savage, Schwenksville, Pa, assignor to KnollAssociates, inc, New York, N.Y., a corporation of New Yorlr Filed May23, 196i, Ser. No. 112,040 4 (Ilairns. (Cl. 248374) The presentinvention relates to tension control mechanism for use in tiltingchairs.

Heretofore the tilting mechanisms for chairs have, for the most part,employed coil springs or rubber torsion sleeves for supporting andcontrolling the tilting movement, and various means have been employedfor adjusting the tension of the spring device of such prior mechanisms.Whatever the merit of the prior means, they all have in common openlyexposed lever mechanisms and hand wheels through which the tension ofthe spring devices is adjusted.

The above described prior devices have not been entirely satisfactoryfor the reason that they quickly accumulate dust and dirt which isdifiicult to remove, particularly from exposed surfaces to which greaseor oil has been applied to ease their operation. Furthermore, the priordevices seldom were in harmony with the appean ance of the chair towhich they were applied.

The mechanical design of the prior tension control devices resultedsolely from the utilitarian requirements imposed on them. Little thoughthas been given heretofore to the visual as well as the mechanicalaspects of chair tension devices. The art or" chair design has been oneof rapid development, yet the best designs are often less effectivebecause they must be used with chair control mechanism which is entirelyunharrnonious therewith.

It is, therefore, an object of this invention to provide a chair tensioncontrol mechanism which has tension adjusting elements that are entirelyenclosed and, therefore, concealed from view.

It is a further object of this invention to provide a chair controldevice which is far more compact than previously believed possible.

it is still another object of this invention to provide a chair tensioncontrol device which has improved tension adjusting means, and which canbe positively operated with the greatest ease in adjusting the tiltingtension of the chair.

The full nature and purpose of these and other objects and advantages ofthe invention and their attainment, will be clear from a reading of thefollowing description in light of the drawings. In the drawings, likereference numerals indicate like parts, and:

FIG. 1 is a side elevational view of a chair in which the chair tensionregulating mechanism herein is installed; FIG. 2 is a front elevationalview of the mechanism;

FIG. 3 is a top plan view;

REG. 4 is a sectional view on the line 44 of PEG. 2;

FIG. 5 is a sectional view on the line 5-5 of FIG. 4; and

FIG. 6 is a fragmentary view showing the manner in which a torsionelement is locked to a bracket casting.

A specific embodiment of my chair tension regulating mechanism includesa bracket casting ill to which the usual chair spindle 12 is firmlyattached, and a chair base casting 14 to which the seat is of a chair isattached. These two castings, when assembled, are adapted to tilt inrespect to each other on a horizontal axis and they provide an enclosurefor the elements of the tension control mechanism. A torsional joint 18interconnects the bracket casting and the base casting coincident withthe horizontal tilting axis. The torsional joint consists of an innersleeve 29 connected to the base casting 14 for rotation therewith, aspaced concentric outer sleeve 22 rotatably carried by the bracketcasting 1d and a torsion element 24 of the elastic material disposedbetween the sleeves 20 and 22. The torsion element 24 is held betweenthe sleeves 20 and 22 under substantial compression and it is bonded tothe sleeves against rotation in respect thereto as shown, for example,in United States Patent 2,087,254 to Walter F. Herold. Finally, a wormgear sector 26 is connected to the outer sleeve 22 of the torsionaljoint and a worm 2?; is mounted in the bracket casting It in operativerelation to the worm gear sector 26 by which the outer sleeve 22 of thetorsional joint is cfiectively connected to the bracket casting ill. Thebracket casting is formed with an upwardly flared face 3t) in whichthere is formed a downwardly opening cavity 32 which is adapted toreceive and substantially enclose the worm 28.

The base casting 14 is a generally annular member providing a flatsurface 34 to which the chair seat 16 is attached. It includesoppositely located depending skirts 36 and 33 in which stay boltpassages 40' and 42 are formed. A stay bolt 44 extends through the staybolt passages 4t and 42 and through the inner sleeve 26 of the torsionaljoint, thus holding the elements assembled and providing an axis onwhich the seat of the chair can tilt.

The base 14 provides an open lower face in which the upper end of thebracket in is seated where it, together with the torsional element 18,is positioned between the depending skirts 36 and 38 of the base 14.

The bracket 16 at its upper end has a pair of mounting collars 46 and 48adapted to snugly embrace the tersional joint 13 while its lower endterminates in a neck 58, having a spindle socket 52 into which the chairspindle 12 is fastened.

The inner sleeve 2d of the torsional joint 18 has formed in the oppositeends thereof locking grooves 54 and 56. These grooves are preferablyformed along the vertical diameter of the sleeve. A complementary pairof lock ribs 58 and 69 are formed in the confronting faces of thedepending skirts 36 and 33 and project toward each other to providemeans by which the inner sleeve 20 of the torsional joint 18 will belocked against rotation when the grooves 54 and 56 of the sleeve are inengagement, respectively, with the lock ribs 58 and 6d. The lock ribs 58and 6t) are formed along an extension of the vertical diameter of thestay bolt passages 40' and 4-2.. Therefore, when the torsional joint 13is put into place between the depending skirts 36 and 38 of the base 14with the lock ribs 58 and so engaged respectively in the grooves $4 and56 of the inner sleeve 29, the inner sleeve will be held immobile in thebase casting.

The stay bolt passage 4t? is countersunk to receive the head 62 of thestay bolt 44, while the passage 42 has screw threads 64 formed thereinto engage corresponding screw threads 66 on the opposite end of the staybolt.

Fixed to the outer sleeve 22 of the torsional joint by means of a setscrew 68 is a gear sleeve 7% which has formed in the face thereof theworm gear sector 25. The worm 28 is mounted in an inwardly projectinglip '72 at the front of and near the upper end of the case 14. Thisplaces the worm 28 into operative engagement with the worm gear sector26, such that when the worm 28 is turned on its shaft 74, it will turnthe gear sleeve 70 and with it the outer sleeve 22 of the torsionaljoint 13. Turning of the worm on its shaft 74 adjusts the torque imposedon the elastic 24 of the joint and, therefore, increases or decreasesthe resistance of the chair to tilting, depending on the direction inwhich the worm 28 is rotated.

The annular chair supporting surface 34, as best seen in FIG. 3, is aninwardly extending flange through which extend a plurality of screwholes 76. The base 14 is first attached to the chair seat 16 preferablywith an interposed mounting plate '78 which has a corresponding numberof screw holes located at points coinciding with the screw holes '76 ofthe base flange. it will be noted that the attaching screws by which thebase 14 is attached to the chair seat are disposed within the annulus ofthe casting and are, therefore, externally invisible.

The annular flange 34 of the base has a slot 36 formed therethroughwhich permits the casting to yield somewhat, if necessary, during theassembling operation.

The outer contour of both the bracket and the base 14 are generallyconical and the major external surface area of the castings, whenassembled, are in continuation of each other along these generallyconical lines, such that the overall effect of the assembly is that ofan inverted, truncated cone.

The invention, therefore, provides a mechanism which is compact,visually pleasing and easy to keep clean. Furthermore, all of theoperating elements are effectively enclosed within the castings suchthat the pleasing external appearance of the mechanism is maintained.

In operation, the chair, when fitted with the mechanism herein, can betilted rearwardly against the tension of the torsional joint 13,increasing the torque on the joint as the chair is tilted rearwardly. Astop 82 formed as an inwardly extending lip at the back of the base 14is adapted to engage an abutment 34 on the bracket 19' to limit 'theextent to which the chair can be tilted backwardly.

In order to adjust the mechanism to provide less or greater resistanceto the tilting motion, it is merely necessary to rotate the Worm. 28 inthe proper direction to place the elastic torsion member 24 under moreor less torque.

While the novel features of the invention have been illustrated anddescribed in connection with a specific embodiment of the invention, itis believed that this embodiment will enable others skilled in the artto apply 7' the principles of the invention in forms departing from theexemplary embodiment herein, and such departures are contemplated by theclaims.

What is claimed is:

1. A chair iron comprising a base casting in the form of an invertedtruncated cone, a pair of oppositely disposed bearing skirtsconstituting a horizontal tilting axis in said base casting, a hollowbracket casting formed generally in external continuation with theexternal contour of said base casting and seated between said bearingskirts, a torsional joint interconnecting said bracket casting and saidbase casting connected with said horizontal tilting axis, said torsionaljoint comprising a first sleeve connected to said base casting, a spacedconcentric second sleeve connected to said bracket casting, and atorsional element of elastic material disposed between said sleeves andjoined to said sleeves against rotation in respect thereto, a worm gearsector connected to the outer or" said sleeves within said base casting,a cavity opening downwardly in the wall of said bracket casting, a wormmounted in said cavity in operative relation to said worm gear sector,said cavity extending through the Wall of said bracket casting providingcontact between said worm gear sector and said worm, a worm mountingshaft seated for rotation in said cavity, and a worm operating shaftwithin said cavity, said torsional joint, said gear sector and said wormbeing substantially enclosed within said castings.

2. The combination defined in claim 1, in which the base of said basecasting is in the form of an annular member adapted to support the seatof a chair.

3. The combination defined in claim 2, in which said annular member ofsaid base casting has a slot formed thereth-rough to impart thereto alimited yielding characteristic.

4. The combination defined in claim 1, in which said cavity extendingthrough the Wall of said bracket casting terminates in an inwardlyprojecting lip and said worm operating shaft is mounted for rotation insaid lip.

References Cited in the file of this patent UNITED STATES PATENTS2,087,253 Herold July 20, 1937 2,087,254 Herold July 20, 1937 2,894,562Peller July 14. 1959

1. A CHAIR IRON COMPRISING A BASE CASTING IN THE FORM OF AN INVERTED TRUNCATED CONE, A PAIR OF OPPOSITELY DISPOSED BEARING SKIRTS CONSTITUTING A HORIZONTAL TILTING AXIS IN SAID BASE CASTING, A HOLLOW BRACKET CASTING FORMED GENERALLY IN EXTERNAL CONTINUATION WITH THE EXTERNAL CONTOUR OF SAID BASE CASTING AND SEATED BETWEEN SAID BEARING SKIRTS, A TORSIONAL JOINT INTERCONNECTING SAID BRACKET CASTING AND SAID BASE CASTING CONNECTED WITH SAID HORIZONTAL TITING AXIS, SAID TORSIONAL JOINT COMPRISING A FIRST SLEEVE CONNECTED TO SAID BASE CASTING, A SPACED CONCENTRIC SECOND SLEEVE CONNECTED TO SAID BRACKET CASTING, AND A TORSIONAL ELEMENT OF ELASTIC MATERIAL DISPOSED BETWEEN SAID SLEEVES AND JOINED TO SAID SLEEVES AGAINST ROTATION IN RESPECT THERETO, A WORM GEAR SECTOR CONNECTED TO THE OUTER OF SAID SLEEVES WITHIN SAID BASE CASTING, A CAVITY OPENING DOWNWARDLY IN THE WALL OF SAID BRACKET CASTING, A WORM MOUNTED IN SAID CAVITY IN OPERATIVE RELATION TO SAID WORM GEAR SECTOR, SAID CAVITY EXTENDING THROUGH THE WALL OF SAID BRACKET CASTING PROVIDING CONTACT BETWEEN SAID WORM GEAR SECTOR AND SAID WORM, A WORM MOUNTING SHAFT SEATED FOR ROTATION IN SAID CAVITY, AND A WORM OPERATING SHAFT WITHIN SAID CAVITY, SAID TORSIONAL JOINT, SAID GEAR SECTOR AND SAID WORM BEING SUBSTANTIALLY ENCLOSED WITHIN SAID CASTINGS. 